1：Experimental Design and Method Selection:

A single-arm, prospective study was conducted to verify the feasibility of SN mapping by ICG fluorescence imaging and metastatic diagnosis by OSNA assay during laparoscopic gastrectomy for early gastric cancer. The primary endpoint was the detection rate of fluorescent lymph nodes. Secondary endpoints included times for procedures, number and distribution of SNs, and adverse effects.

2：Sample Selection and Data Sources:

Patients with clinical T1N0M0 gastric adenocarcinoma, single primary lesion ≤4 cm, no prior treatment, and no faint positive reactions in preoperative immunohistochemical staining for CK19 were included. Exclusion criteria included drug allergies, active asthma, apparent T2-T4 tumors, or extensive abdominal adhesions.

3：List of Experimental Equipment and Materials:

Equipment included laparoscopic systems (K26003 BGA HOPKINS? ICG telescope from KARL STORZ or VISERA ELITE II telescope IR from OLYMPUS), OSNA assay system (RD-100i from Sysmex), ICG (Diagnogreen from Dai-Ichi Sankyo Pharm.), endoscopic puncture needle, and laboratory consumables (LYNORHAG lysis buffer, LYNOAMP BC gene amplification reagent from Sysmex).

4：Experimental Procedures and Operational Workflow:

Under pneumoperitoneum, ICG was injected endoscopically around the tumor. Fluorescence imaging was performed for up to 20 minutes to identify SNs, which were excised. OSNA assay was conducted on SNs intraoperatively to detect CK19 mRNA. Laparoscopic gastrectomy with lymph node dissection followed.

5：Data Analysis Methods:

Data on patient demographics, surgical variables, SN mapping results, and OSNA assay outcomes were collected. Statistical analysis involved medians and ranges for continuous variables, and proportions for categorical variables.